the y intercept is where it hits the y axis that is how far up or down so then it tells you to transform it 3 units down just find the y intercept then minus 3 from it
ok y intercept is where line crosses y axis or where x=0
so set x=0 and solve for y
6(0)+5y=-15 0+5y=-15 5y=-15 y=3 is the y intercept
translate 3 units down so 3-3=0 y=0 is the y intercept after transformation (should be translation)